The Happy Effect Exercise Has On Your...Gut Bacteria?

Gut bacteria is one of the hottest topics of scientific research. That’s delightful for health journalists, because the things that influence your gut are so random and irresistible: everything from dirty farmers’ market veggies to slobbery dogs can improve yours by leaps and bounds.

With a ratio of 10 bacterial cells to every 1 human cell, we’re more bug than human, so it makes sense that nearly everything affects your microbiome (science-speak for your unique community of bacteria.) And as of today, you can add exercise to that list of influencers, finds a new study published in the journal Gut.

Researchers from the University College Cork in Ireland studied the gut bugs of 40 professional rugby players, courtesy of their generous fecal donations. Their poop’s DNA revealed that they had microbiomes far more diverse than those of two control groups of normal people.

That’s good news for professional athletes: Microbial diversity may be an important indicator of health, and the loss of diversity is associated with many disorders, including obesity. Rugby players sported more types of bacteria associated with protein consumption, higher levels of creatine kinase (a marker of extreme exercise), and better metabolic profiles. But most surprisingly to the scientists, the athletes also had lower inflammatory markers, which was a shock because of the amount of trauma they were doing to their muscles. “We think that may have something to do with their microbiota, because in disorders where you reduce the diversity of your microbiota, you tend to get an increased risk of inflammation,” said Fergus Shanahan, study author and head of the Department of Medicine and Alimentary Pharmabiotic Centre at University College Cork.

Luckily for the non-rugby-playing rest of us, the trend of bacterial diversity trickled down from elite-athlete status. “The fitter the control, the more likely they’d have a diverse microbiota as well,” Shanahan said.

How could working out affect your levels of bacteria? “Exercise does a lot of things that are not obvious. It’s not just about cardiovascular fitness,” said Shanahan. Exercise has long been known to boost the immune system, lower inflammation, alter hormones, and improve stress responses. It even increases the motility of the bowel. “We’ve known for years that if constipated people go and exercise, it actually helps their constipation,” he said. How that works is still somewhat of a mystery, but it’s one more point for the exercise-gut team.

Diet is the more-studied influencer on gut bacteria, and diet appears to work in conjunction with exercise. Extreme exercise is accompanied by an extreme diet, and rugby players eat more of everything—but especially protein, in the form of meat and supplements like whey protein. Other studies have shown that protein-rich diets are associated with more diverse bacterial colonies, but “we’ve never seen this degree of an impact,” Shanahan said. Exercise seems to enhance protein’s effect on diversity.

The researchers were so excited by the data that they’re going to try the experiment on normal people to see how much exercise you’d have to do to get the gut-diversifying effects. Here's hoping you don't need rugby-size proportions of exercise to get all those extra gut bugs.